To answer your question, yes. Is it difficult? No! This is a very impractical method to adopt and I recommend using HTML only and using a php script to analyze the sent material. All you have to do is echo the html form in the php file. Here is an example of a simple form created in PHP:
<?php
echo "
<head>
<title>Simple Form in PHP</title>
</head>
<body>
<form action='script.php' method='post'>
Username: <input type='text' name='username'>
Password: <input type='text' name='password'>
<input type='submit' name='Go!'>
</form>
</body>
Now, you need to make sure you have a script, most likely PHP, ready to analyze the variables that have been sent to it from the form!
Sincerely,
André LeFort